TGF-beta and HGF transmit the signals through JNK-dependent Smad2/3 phosphorylation at the linker regions

Oncogene. 2004 Sep 23;23(44):7416-29. doi: 10.1038/sj.onc.1207981.


Although hepatocyte growth factor (HGF) can act synergistically or antagonistically with transforming growth factor-beta (TGF-beta) signaling, molecular mechanism of their crosstalk remains unknown. Using antibodies which selectively distinguished receptor-regulated Smads (R-Smads) phosphorylated at linker regions from those at C-terminal regions, we herein showed that either HGF or TGF-beta treatment of normal stomach-origin cells activated the JNK pathway, thereafter inducing endogenous R-Smads phosphorylation at linker regions. However, the phosphorylation at their C-terminal regions was not induced by HGF treatment. The activated JNK could directly phosphorylate R-Smads in vitro at the same sites that were phosphorylated in response to TGF-beta or HGF in vivo. Thus, the linker regions of R-Smads were the common phosphorylation sites for HGF and TGF-beta signaling pathways. The phosphorylation induced by simultaneous treatment with HGF and TGF-beta allowed R-Smads to associate with Smad4 and to translocate into the nucleus. JNK pathway involved HGF and TGF-beta-mediated infiltration potency since a JNK inhibitor SP600125 caused the reduction of invasive capacity induced by HGF and TGF-beta signals. Moreover, a combined treatment with HGF and TGF-beta led to a potent increase in plasminogen activator inhibitor type 1 transcriptional activity through Smad3 phosphorylation at the linker region. In contrast, HGF treatment reduced TGF-beta-dependent activation of p15INK4B promoter, in which Smad3 phosphorylation at the C-terminal region was involved. In conclusion, HGF and TGF-beta transmit the signals through JNK-mediated R-Smads phosphorylation at linker regions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • DNA-Binding Proteins / metabolism*
  • Genetic Vectors
  • Hepatocyte Growth Factor / pharmacology*
  • JNK Mitogen-Activated Protein Kinases*
  • MAP Kinase Kinase 4
  • MAP Kinase Signaling System / drug effects
  • MAP Kinase Signaling System / physiology
  • Mitogen-Activated Protein Kinase Kinases / metabolism*
  • Phosphorylation
  • Rats
  • Recombinant Proteins / metabolism
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*
  • Smad2 Protein
  • Smad3 Protein
  • Stomach
  • Trans-Activators / metabolism*
  • Transforming Growth Factor beta / pharmacology*


  • DNA-Binding Proteins
  • Recombinant Proteins
  • Smad2 Protein
  • Smad2 protein, rat
  • Smad3 Protein
  • Smad3 protein, rat
  • Trans-Activators
  • Transforming Growth Factor beta
  • Hepatocyte Growth Factor
  • JNK Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 4
  • Mitogen-Activated Protein Kinase Kinases